CANADA

Clifford J. Mugnier, C.P., C.M.S.

The contents of this column reflect readjustments included: the Prince relative merits of aesthetics versus the views of the author, who is responsible for Edward Island free adjustment of convenience for artillery fire control. the facts and accuracy of the data presented herein. The contents do not necessarily 1968, the 1971 Newfoundland On sheets of the NTS that were of use reflect the official views or policies of the adjustment, the 1972 Nova Scotia to the military, the Army added a American Society for Photogrammetry and readjustment, the Southern Ontario 1000-yard rectangular grid overprint Remote Sensing and/or the Louisiana State University adjustment of 1974, the Northwestern based on the Army Lambert systems. Center for GeoInformatics (C4G). Ontario adjustment of 1974 and the That was called the “British Grid,” a Southern Quebec adjustment of 1978. system introduced in England in 1919 The Dominion of Canada was With the advent of the Transit and adopted by many Commonwealth established in 1867 by the union of satellite system, the Maritime countries. Later changed to the New Brunswick and Nova Scotia with Scientific Adjustment (MSA) was “Modified British Grid,” it was also the Provinces of Canada. The Statute developed in 1971. The Canadian overprinted on many existing Army of Westminster of 1931 removed the Council on Surveying and Mapping one-inch maps cast on the polyconic U.K. Parliament authority over the adopted a resolution (23 June 1975) projection. The “Modified British dominions and the constitution was that the Geodetic Survey of Canada Grid” did not have the failing that patriated to Canada in 1982. The (now Geomatics Canada) should make numerical references would repeat original geodetic surveys of Canada an adjustment in 1977 of the primary themselves every 10,000 yards, but were computed on the Bessel 1841 horizontal control net of Canada on would continue differently until ellipsoid. In 1880, when the U.S. the NAD1927. Only the Maritime 100,000 yards, a decided safety Coast & Geodetic Survey chose to Provinces are still on the Average advantage to avoid calling “friendly” adopt the ellipsoid that had been Terrestrial System (ATS 77), and they artillery fire onto your own positions. published by Colonel A. R. Clarke of have not yet moved to NAD83 or The Canadian Lambert projection the British Royal Engineers in 1866 WGS84. grids continued in use until the one- for North America, it was only logical Early one-inch maps of inch series was converted by the Army for Canada to adopt the same Canada (one inch equals one statute Survey Establishment to 1:50,000 ellipsoid. The original first-order mile) by the Geological Survey of scale maps in 1948 with the UTM grid geodetic networks included only a few Canada as of 1844 were based on the system and the associated Military networks in Canada. With a few polyconic projection until the Army Grid Reference System (MGRS). second-order networks, they were replaced it with the 1932 Lambert In 1945, a special Lambert adjusted between 1927 and 1932 to Conformal Conics that included the Conformal Conic projection was produce the original system of Maritime Zones and the Eastern established for Prince Edward Island coordinates known as NAD27. Zones. Although the U.S. military was and later changed to an oblique double Southern Quebec, Ontario, and the using the World Polyconic Grid stereographic in 1959 along with a southern boundary of the Western system in U.S. Survey yards separate stereographic zone for New provinces were included. (3600/3937), the Lambert projection Brunswick. Some time after World Subsequently, first-order arcs were sheets of the Canadian Army were War II, probably also in 1959, five 3- extended northwards from stations in gridded in International yards (1 inch degree wide Gauss-Krüger Transverse the original figures and were adjusted = 2.54 cm.). On the other hand, Mercator belts were established for while holding the original stations Topographical Surveys, part of the eastern Canada, but seem to have been fixed. Department of the Interior, published actually used only for a couple belts This practice was the same as one sheet in 1926 on the polyconic covering Nova Scotia. These two used in the U. S. and Mexico with projection, and from 1927 on used the belts (zones 4 and 5) were used with respect to new observations made after Deville-Peters 1924 Transverse the millions digit of the False Easting the original datum adjustment. The Mercator (Gauss) projection with 8 being equal to the zone number. North American Datum of 1927 was a degree zones for the National Although this convention is not spectacular achievement in geodesy at Topographic Series (NTS). uncommon throughout the world, this the time. In certain cases, local There was a lively discussion is the only such usage known with datums were later computed for (and correspondence) for years respect to False Eastings for North optimum accuracy at the expense of between the two mapping America. overall continuity. Some of the major organizations that centered on the The grid systems established

in 1959 for the Maritime Provinces were later documented (1970’s) in a series of publications from the University of New Brunswick which are among the most elegant ever written for the computational use by geodetic surveyors and mappers. These documents are genuine “how to” books and not just math proofs. Those readers that are interested in the topics of this column are strongly urged to obtain copies of this series by Thompson, Krakiwsky, et. al. As the Provinces move towards the adoption of NAD83, a change in grid systems is inevitable. Current plans for New Brunswick are to retain the Oblique Double Stereographic, but the False Easting will be changed to 3500 Km and the False Northing will be changed to 4500 Km. All other constants will remain the same, excepting the ellipsoid. The Province of Quebec will use the “Modified Transverse Mercator” (MTM) with eight zones of 3° (2 to 10 from east to west), for example; zone 7 has a central meridian of 70° 30' W. The scale factor at origin is 0.9999 and the False Easting is 304800 meters for all zones. All other provinces seem to be content with the NAD83 UTM (for now). Surprisingly, not a single Province seems interested (or is aware of) in changing the ellipsoid parameters to simplify the sea-level reduction for GIS/survey applications as done by Minnesota, Wisconsin and Colombia. The Canadian national government and some provinces have gotten commercial in their support (for a price) of transforming to NAD83. The software to convert Latitude & Longitude between the NAD27 and the NAD83 is available for a couple hundred dollars, the geoid software is available for several hundred dollars more. The Canadian government also offers a GPS correction service for a price.

PE&RS December 1997